72 



PALJiONTOLOGY OF NEW-YOKK. 



Fig. 7 a, b. Dorsal and ventral valve of a full grown specimen. 

 Fig. 7 c. Profile view of the same. 



Fig* 7 d. Front view of the same, showing the three plications in the mesial sinuSj and four on 

 the elevation. 



Position and locality. In the upper limestone of this group at Lockport. 



{Collection of Cul. Jkwett.) 



460. 31. ATRYPA RETICULARIS. 



^ PL. XXIII. Fig. 8 a- e. 



jlnomia reticularis. LinNe, 1767, Syst. Naturae, 12th ed., Vol. i, p. 1152 ; 1798, Encyclop. 



Methodique, pi. 242, fig. 4 a, b, c. 

 T^erebratulithus prisons. Schlotheim, Petrefactae, 1820 : Nachtrage, pi. 17, fig. 2 ; pi. 20, 



fig. 4. 



— explanatus. Id. Ibid. p. 263 ; Nachtrage, pi. 18, fig. 2. 



Anomites reticularis. Wahlenberg, 1821, Act. See. Sci. Upsalensis, Vol. viii, p. 65, no. 6. 

 Terebratula ajjinis. SoWerby, 1823, Min. Conchology, Vol. iv, pag. 24, pi. 324, fig. 2. 

 Atrypa reticularis. Dalmaiv, 1827, Vet. Acad. Handlingar, pag. 127, pi. 4, fig. 2. 

 Terebratula cancellata. Eichwald, 1829, Zool. sp.. Vol. i, pag. 276, pi. 4, fig. 11. 

 Porambonites maxima. Pander, 1830, Beitr. zur Geogn. Eussland, pi. 16 B, fig. 7. 

 Terebratula prisca. Lamarck, 1836, Anim. sans Vertebres, 2d edit., Vol. vii, p. 365. 



— reticularis. Bronn, 1887, Loth. Geognostica, page 72, pi. 2, fig. 10. 



— prisca. Pusch, 1838, Polen's Palaeontologie, p. 26. 



— — Von Buck, 1838, Mem. Soc. Geol. de France, Vol. iii, pi. 16, fig. 19. 

 Atrypa affinis. J. Sowerby, 1839, in Murchison's Sil. System, pi. 6, fig. 5. 



— aspera. Id. 1839, in Sil. System, pi. 12, fig. 6. 



— reticularis. Hisinger, 1839, Leth. Suecica, pag. 75, pi. 21, fig. 11 a, b, c, d, e 

 Terebratula prisca. Vow Buch, 1840, Beitr. zur Geog. Tlussland. 



— — J. Sowerby, 1840, Geol. Transactions, 2d series, Vol. v, p. 703. 

 j/ltrypa aspera. Id. Ibid. pi. 56, fig. 28. 



Terebratula prisca. Eichwald, 1840, Sil. Syst. in Esthl., p. 141. 



— armiger. Id. apud Von Buch, 1840, Beitr. zur geog. Russland, p. 108. 

 Atrypa prisca. Phillips, 1841, Pal. Fossils, pi. 33, fig. 145. 



— affinis. Vanuxem, Geol. Rep. 3d Dist. N. York, 1842, p. 88. 



— — Hall, Geol. Rep. 4th District, 1848, p. 108. 



Terebratula reticularis. De Verneuil, Geol. Russia and the Ural Mts., 1845, p. 9, pi. x, fig. 



12 a, b, c. 



Shell subrotund, more or less compressed, subtruncated above or on the hinge-line ; valves 

 more or less equal, the beak of the dorsal valve extending beyond the ventral valve, and the 

 latter being deeper and more convex in older specimens ; surface marked by dichotomous 

 rounded striee, which are crossed by concentric elevated lamellEe, giving a reticulated or de- 

 cussated character to the surface. 



It is impossible to give a definite description of this very protean species, which commences 

 its existence in the Clinton group, and continues under various modifications through the suc- 

 ceeding strata as far as the Chemung group. In each of its geological positions, however, it 

 presents peculiar characters, and we are able to decide at once the geological position of spe- 

 cimens, by these peculiarities. 



